##### 7.1.3.1.2 ECDSA
The CA SHALL indicate an ECDSA key using the id-ecPublicKey (OID: 1.2.840.10045.2.1) algorithm identifier. The parameters MUST use the `namedCurve` encoding.
* For P-256 keys, the `namedCurve` MUST be secp256r1 (OID: 1.2.840.10045.3.1.7).
* For P-384 keys, the `namedCurve` MUST be secp384r1 (OID: 1.3.132.0.34).
* For P-521 keys, the `namedCurve` MUST be secp521r1 (OID: 1.3.132.0.35).
When encoded, the `AlgorithmIdentifier` for ECDSA keys MUST be byte-for-byte identical with the following hex-encoded bytes:
* For P-256 keys, `301306072a8648ce3d020106082a8648ce3d030107`.
* For P-384 keys, `301006072a8648ce3d020106052b81040022`.
* For P-521 keys, `301006072a8648ce3d020106052b81040023`.